Acute pancreatitis laboratory findings
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Raviteja Guddeti, M.B.B.S. [2]
Overview
Laboratory Findings
- Blood Investigations - Full blood count, Renal function tests, Liver Function, serum calcium, serum amylase and lipase, Arterial blood gas
Amylase and lipase
- Serum amylase and lipase may be used in the making of the diagnosis of acute pancreatitis.
- Serum amylase usually rises 2 to 12 hours from the onset of symptoms, and normalizes within 48-72 hours.
- Serum lipase rises 4 to 8 hours from the onset of symptoms and normalizes within 7 to 14 days.
- Serum amylase may be normal (in 10% of cases) for cases of acute on chronic pancreatitis (depleted acinar cell mass) and hypertriglyceridemia.
- Reasons for false positive elevated serum amylase include salivary gland disease (elevated salivary amylase) and macroamylasemia.
- If the lipase level is about 2.5 to 3 times that of Amylase, it is an indication of pancreatitis due to Alcohol [1].
Regarding selection of these tests, two practice guidelines state:
- "It is usually not necessary to measure both serum amylase and lipase. Serum lipase may be preferable because it remains normal in some nonpancreatic conditions that increase serum amylase including macroamylasemia, parotitis, and some carcinomas. In general, serum lipase is thought to be more sensitive and specific than serum amylase in the diagnosis of acute pancreatitis" [2]
- "Although amylase is widely available and provides acceptable accuracy of diagnosis, where lipase is available it is preferred for the diagnosis of acute pancreatitis (recommendation grade A)"[3]
Most (PMID 15943725, PMID 11552931, PMID 2580467, PMID 2466075, PMID 9436862), but not all (PMID 11156345, PMID 8945483) individual studies support the superiority of the lipase. In one large study, there were no patients with pancreatitis who had an elevated amylase with a normal lipase [4]. Another study found that the amylase could add diagnostic value to the lipase, but only if the results of the two tests were combined with a discriminant function equation [5].
References
- ↑ Gumaste V, Dave P, Weissman D, Messer J (1991). "Lipase/amylase ratio. A new index that distinguishes acute episodes of alcoholic from nonalcoholic acute pancreatitis". Gastroenterology. 101 (5): 1361–6. PMID 1718808.
- ↑ Banks P, Freeman M (2006). "Practice guidelines in acute pancreatitis". Am J Gastroenterol. 101 (10): 2379–400. doi:10.1111/j.1572-0241.2006.00856.x. PMID 17032204.
- ↑ UK Working Party on Acute Pancreatitis (2005). "UK guidelines for the management of acute pancreatitis". Gut. 54 Suppl 3: iii1–9. doi:10.1136/gut.2004.057026. PMID 15831893.
- ↑ Smith R, Southwell-Keely J, Chesher D (2005). "Should serum pancreatic lipase replace serum amylase as a biomarker of acute pancreatitis?". ANZ J Surg. 75 (6): 399–404. doi:10.1111/j.1445-2197.2005.03391.x. PMID 15943725.
- ↑ Corsetti J, Cox C, Schulz T, Arvan D (1993). "Combined serum amylase and lipase determinations for diagnosis of suspected acute pancreatitis". Clin Chem. 39 (12): 2495–9. PMID 7504593.